Prostheses for various implantation systems are, of course, well known. For those individuals, however, experiencing serious spinal ailments and infirmities, very little has been accomplished in the nature of prosthetic devices for use in the vertebral column. Thus, patients having primary and/or metastatic malignant tumors not responding to other therapy, or experiencing intense and persistent backbone pain caused by tumorous vertebrae, or spinal cord compression with paresis or paraplegia, or having vertebral collapse or backbone instability, have not heretofore had available to them a prosthesis for alleviating these maladies.